In the CD-ROM industry, there is an ever-increasing competition to increase the rate at which the data can be transferred from a CD-ROM disc to a peripheral device (hereinafter the terms "speed" or "CD-ROM speed" or "data transmission speed" shall be used to denote the rate at which data is transferred, and should be distinguished from "rotational speed" which refers to the rate at which a CD-ROM disc rotates or spins in the disc drive). This is understandable since higher speed usually means less waiting time for the user. The earliest commercially available CD-ROM drive utilized a similar technology as that of an audio CD player and achieved a comparable speed (hereinafter referred to as single-speed or 1x). Soon thereafter, the industry introduced dual-speed or 2x drives, quad-speed or 4x drives, and currently the 8x drives.
In order to achieve the higher speeds, the drive must be able to spin the disc at correspondingly increased rotational speeds. So for instance, a 4x drive should be able to spin the CD-ROM disc about twice as fast as that of a 2x drive. With increased speeds (hence increased rotational speeds), however, the disc experiences increased vibration. This vibration, which increases exponentially with speed, is a serious problem which can significantly hinder the drive's performance. Intermittent data streaming, for example, is one such a problem where the drive is unable to read some of the data off the CD-ROM. This problem may make video applications inoperable, or may unduly slow down other applications due to extended error recovery time.
Furthermore, there may be other hardware problems or constraints which may degrade the performance of the CD-ROM drive. For instance, the drive motor may exceed its maximum rotational speed, or the drive may experience resonance. This is why although there currently exist 8x drives, the performance is quite poor as evidence by the negative review of the first 8x drive in an article from the 1995 December issue of PC World entitled "First 8x CD-ROM Drive Doesn't Live Up To Its Name."
Although some higher speeds can conceivably be achieved without compromising performance, this would require significant improvement in the current drives' hardware design, and would require extensive modification. In fact, to the best of the inventors' knowledge, no commercially available CD-ROM hardware currently exists which can consistently run a CD-ROM disc at 8x speed without experiencing significant performance problems.
Hence, for now, there is generally a compromise between speed and performance. So while higher speed is highly desirable and may be achieved using current CD-ROM technology, it is undesirable to degrade the integrity of the data transmission. On the other hand, while it is desirable to have error-free transmission, it is undesirable to operate the drive at a speed lower than its maximum potential.
The current CD-ROM drives do not operate at their maximum potential; they either suffer from poor data transmission due to excessive speed (or lower speed than that claimed due to increased error recovery time), or do not operate at the highest speed they are capable of running. The currently-available 8x drives (as alluded to above) are an example of CD-ROM drives which suffer from poor data transmission as a result of the drive being operated at its near-maximum speed. The currently-available 4x drives (actually also the 2x and 1x drives) are an example of drives which operate below their maximum speed.
The primary reason for this shortcoming is that the drives are only capable of operating at one speed even though higher speeds are possible at times without serious degradation in performance, provided that certain parameters are met. The current drives, however, lack the proper means to account for these parameters, and therefore, are relegated to either operating at a below-optimum speed to ensure consistent data transmission for all situations, or operating at an excessively high-speed which cannot be maintained continuously without encountering transmission errors.
Therefore, in light of these shortcomings, it would be highly desirable to have a method and apparatus for the optimization of the operating speeds for current-available CD-ROM drives to facilitate maximum performance without requiring extensive hardware modification.